#include <bits/stdc++.h>
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
const ll ILL=2167167167167167167;
const int INF=2100000000;
#define rep(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define all(p) p.begin(),p.end()
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,T b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,T b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
bool yneos(bool a,bool upp=0){if(a){cout<<(upp?"YES\n":"Yes\n");}else{cout<<(upp?"NO\n":"No\n");}return a;}
template<class T> void vec_out(vector<T> &p,int ty=0){
    if(ty==2){cout<<'{';for(int i=0;i<(int)p.size();i++){if(i){cout<<",";}cout<<'"'<<p[i]<<'"';}cout<<"}\n";}
    else{if(ty==1){cout<<p.size()<<"\n";}for(int i=0;i<(int)(p.size());i++){if(i) cout<<" ";cout<<p[i];}cout<<"\n";}}
template<class T> T vec_min(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmin(ans,x);return ans;}
template<class T> T vec_max(vector<T> &a){assert(!a.empty());T ans=a[0];for(auto &x:a) chmax(ans,x);return ans;}
template<class T> T vec_sum(vector<T> &a){T ans=T(0);for(auto &x:a) ans+=x;return ans;}
int pop_count(long long a){int res=0;while(a){res+=(a&1),a>>=1;}return res;}
template<class T> bool inside(T l,T x,T r){return l<=x&&x<r;}

#include <atcoder/modint>
using mint = atcoder::modint998244353;
#include <atcoder/convolution>

void solve();
// CYAN / FREDERIC
int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int t = 1;
    // cin >> t;
    rep(i, 0, t) solve();
}

void solve(){
    ll N, H;
    cin >> N >> H;
    if (N == 1){
        cout << ((mint)(3) / (mint)5).val() << "\n";
        return;
    }
    using F = array<array<vector<mint>, 3>, 3>;
    F base;
    vector<mint> inv(4);
    rep(i, 1, 4) inv[i] = (mint)(1) / (mint)(i);
    base[0][0] = {inv[2]};
    base[0][1] = {0, inv[2]};
    base[1][0] = {inv[3]};
    base[1][1] = {0, inv[3]};
    base[1][2] = {0, inv[3]};
    base[2][1] = {0, 2 * inv[3]};
    base[2][2] = {0, inv[3]};
    auto add = [&](vector<mint> &a, vector<mint> b) -> void {
        rep(i, 0, b.size()){
            if ((int)a.size() == i) a.push_back(0);
            a[i] += b[i];
        }
    };
    auto mul = [&](F l, F r) -> F {
        F base;
        rep(i, 0, 3) rep(j, 0, 3) base[i][j] = {0};
        rep(i, 0, 3) rep(j, 0, 3) rep(k, 0, 3) add(base[i][k], atcoder::convolution(l[i][j], r[j][k]));
        return base;
    };
    auto my_pow = [&](F l, int t) -> F {
        F base;
        rep(i, 0, 3) rep(j, 0, 3) base[i][j] = {(i == j ? 1 : 0)};
        while (t){
            if (t & 1){
                base = mul(base, l);
            }
            t /= 2;
            l = mul(l, l);
        }
        return base;
    };
    auto f = my_pow(base, N - 1);
    mint ans = 0;
    rep(i, 0, 3) rep(j, 0, 3){
        mint tmp = 0;
        rep(k, H - min(1, i), f[i][j].size()) tmp += f[i][j][k];
        if (i != 2) tmp *= 2;
        ans += tmp;
    }
    cout << (ans / 5).val() << "\n";
}